Correction of Severe Bimaxillary Protrusion

Robby Ramadhonie

INTRODUCTION• Bimaxillary dentoalveolar protrusion is a common dentofacial deformity that results in

functional and esthetic problems.• Patients with severe bimaxillary dentoalveolar protrusion are often treated with a

combination of orthodontics and orthognathic surgery to improve the facial profile.• In adult patients with bimaxillary protrusion, correction may involve removal of f our

premolars. The anterior teeth may be retracted with fixed appliances, with or without orthognathic surgery.

• In severe cases of protrusion, the typical orthodontic therapy that includes extraction of the 4 first premolars and retraction of anterior teeth may not be sufficient to improve the facial profile.

• total arch distalization might be required to supplement the extraction treatment if patients decline surgical options to improve their profiles.

• A modified palatal anchorage plate (MPAP) may overcome this drawback and effectively distalize the whole dental arch

• A corticotomy technique to enable the movement of a bone segment that includes a tooth by sectioning of the layer of compact bone. It is a surgical technique which allows the fairly rapid movement of a tooth or group of teeth without requiring the teeth to move a great distance through bone. A corticotomy poses less risk than a segmental osteotomy or orthognathic surgery

CASE REPORT I• A young woman, aged 20 years 4 months, came to the orthodontic department

of Seoul St. Mary's Hospital, Catholic University of Korea, in Seoul with the chief complaint of lip protrusion.

• Her lips were incompetent because of the severe proclination of her maxillary incisors at rest. When smiling, the left side of her upper lip lifted more than the right.

• No significant skeletal asymmetry or temporomandibular joint disease was found.

• She was healthy, with no specific medical problems.• She had an overjet of 6.5 mm, a 10% overbite, and mild crowding in both arches. • She had Class I molar relationships and dental caries on her mandibular second

molars.• The panoramic radiograph showed a missing mandibular left third molar, and her

other third molars were in the developmental stage

Pretreatment facial and intraoral photographs

The panoramic radiograph showed a missing mandibular left third molar, and her other third molars were in the developmental stage.

The lateral cephalometric analysis indicated a skeletal Class I pattern (ANB, 3.5; Witsappraisal,1.0 mm) with a hyperdivergent growth pattern (FMA, 33.0). The maxillary and mandibular incisors were proclined (U1-FH, 135.0; IMPA, 94.5;U1/L1,97.5). The upper and lower lips were protrusive (upper lip to E-line, 2.5 mm; lower lip to E-line, 5.0 mm) with an acute nasolabial angle (79.0). She had a short upper lip (subnasale-stomion, 17.0 mm) with an increased ratio of lower lip and chin to upper lip (stomion-soft tissue menton/subnasale-stomion, 3.0)

TREATMENT OBJECTIVES

The treatment objectives were to improve the patient's facial profile, obtain optimal inclination of her anterior teeth, obtain normal overjet and overbite, maintain a Class I molar and canine relationship, and resolve the crowding in both arches.

TREATMENT ALTERNATIVES

The first treatment option was to perform an anterior segmental osteotomy combined with first premolar extractions because of her thin anterior alveolus. The second treatment option was to fully retract her anterior teeth after extraction of her first premolars. However, if the improvement in her profile was not satisfactory after closure of the extraction space, a further treatment option was to distalize the entire maxillary dentition using a palatal plate appliance. The mandibular dentition would be distalized along with the maxillary dentition using Class III elastics.The patient refused the surgical treatment option. Therefore, the second and the additional treatment options were used to improve her profile.

TREATMENT PROGRESS• Before orthodontic treatment, the patient was referred to a general dentist for treatment of

the dental caries and extraction of all first premolars.• She was also sent to an oral surgeon to evaluate the extraction of her third molars, but she

declined the extractions. • Preadjusted appliances with 0.022-in slots were bonded on both arches for leveling and

alignment.• Her maxillary arch was leveled with archwires. two miniscrews were placed between the

maxillary first and second molars for maximum anchorage. • The maxillary and mandibular anterior teeth were retracte.• Unfortunately, even after retraction of the maxillary anterior segment with maximum

anchorage, the patient still had protrusive lips.• Therefore, to improve her profile, an MPAP was used to distalize the whole dentition of both

arches.• A palatal arch running along the gingival margin was soldered to the banded maxillary first

molars.• At the finishing stage, final detailing of the occlusion was accomplished with 0.0163 0.022-in

stainless steel archwires in conjunction with posterior vertical and Class III elastics. Bonded lingual premolar to premolar retainers were placed on both the maxillary and mandibular dentitions, and additional Essix retainers were delivered.

• Total treatment time was 24 months.

CASE REPORT II• This female patient, aged 50 years, 10 months, presented with

pronounced dental and labial protrusion, and advanced periodontal disease. Pocket depths ranged from 4 - 8 mm. All molar furcations were affected, and the mandibular incisors were over-erupted.

• She was treated with universal curettage and periodontal surgery, and followed until basic periodontal health was evident.

• The extraoral examination revealed a very convex profile with significant mentalis muscle strain.

• The intraoral examination revealed a Class II canine and Class I molar relationship.

• In the maxilla, the anteriors were spaced and severely protruded. The mandibular anteriors were moderately crowded.

Lateral cephalometric view revealed that the patient had a skeletal Class II relationship (ANB angle = 3.2o, Mx.1 to NA angle = 30.7o, Mx.1 to NA distance = 11.5 mm), a steep occlusal plane (SN-OP angle = 20.6o), a high mandibular plane angle (FMA = 32.2o), and proclined incisors (Interincisal angle = 114.4o, Mandibular incisor to NB angle = 31.7o, Mandibular incisor to NB distance = 12.3 mm) (Fig 3A, Table 1).

• The diagnosis was a skeletal Class II malocclusion with bidentoalveolar protrusion and compromised periodontal status.

• The panoramic radiogram revealed a missing lower right first molar. The periodontal bone levels were low.

• TREATMENT OBJECTIVESThe treatment objectives based on the analysis of the cephalometric tracings, dental x-rays, photographs, and study models were to extract all the first premolars, align and retract the anterior teeth, improve the interincisal angle relationship, decrease the lip protrusion, maintain the posterior occlusal relationship, and improve the convex profile - all without a deterioration of the periodontal condition.

TREATMENT ALTERNATIVES• Fixed appliances with removal of two maxillary pre-molars and

two mandibular incisors, retracting the maxillary anterior teeth against mini-screw anchors.

• Remove the upper and lower first premolars. Then perform a corticotomy to outline a block of bone around the maxillary anteriors and retract the mandibular anteriors with an anterior segmental osteotomy under local anesthesia. Use the C-lingual retractor and C-plate in the maxilla as rigid anchorage.

• Remove the four first premolars and perform anterior segmental osteotomies in both arches to affect the retraction surgically under general anesthesia.

• The patient chose the second option even though she was made aware that the lower anterior teeth were more periodontally at risk than the lower first premolars. She noted the advantages of a shortened treatment time and felt the overall risks were less.

TREATMENT PROGRESS• After a three month stabilization of the periodontal status, and

home care was improved, the designated teeth were removed and corticotomy was performed in the maxilla, and anterior segmental osteotomy performed in the mandible under local anesthesia.

• Two weeks later, to allow reconnection of the palatal blood supply after the palatal corticotomy, a buccal corticotomy was executed and a C-plate, a C-lingual retractor and a C-tube were installed (Figs.5A and 6).

• Fixed orthodontic appliances were placed on the maxillary posterior teeth and lower teeth, followed by the mandibular anterior segmental osteotomy.

• In the mandible, after a healing period of about 6 weeks, leveling and alignment began. In the maxilla, retraction of the anterior corticotomized segment required five months, after which the C-lingual retractor was removed and anterior brackets placed for four more months to level and align the anterior teeth

CONCLUSION• A combination of extraction treatment and total arch distalization

might be a feasible treatment option to avoid surgery in patients with moderate bimaxillary protrusion and achieve better facial esthetics. The application of the palatal anchorage plate shows the correction of a severely protrusive soft tissue profile without orthognathic surgery by 4 first premolar extractions along with total distalization

• As shown in this reported case of an adult with severe periodontal disease and bimaxillary protrusion careful treatment of periodontal disease and appropriate periodontal maintenance during treatment allowed a protocol of treatment using perisegmental corticotomy and skeletal anchorage under local anesthesia to provide a correction that could be used as an alternative to orthognathic surgery

Daftar Pustaka

• Seong-Hun Kim, dkk. Severe bimaxillary protrusion with adult periodontitis treated by corticotomy and compression osteogenesis. Vol. 39, No. 1, 2009. Korean J Orthod.

• Yoon-Ah Kook, dkk. Correction of severe bimaxillary protrusion with first premolar extractions and total arch distalization with palatal anchorage plates. American Journal of Orthodontics and Dentofacial Ortho, Vol.148. 2015.

TERIMA KASIH

MOHON ASUPAN